Local network access points (e.g., WiFi network access points) that allow devices (e.g., mobile phones and laptop computers) to access a network are well-known and found in many different locations. Some local networks may be associated with a geographic location and may be used by a device to determine the geographic location of the device. In one implementation, a database stores an association of network identifiers, e.g., media access control (MAC) addresses, and geographic locations. The database may allow a device that is connected to a local network to quickly determine its geographic location based on the network identifier of a local network accessible to the device.